Lighting fixture support for a tubular electric lamp



Feb. 21, 1967 v H. DAHLHAUS 3,305,823

LIGHTING FIXTURE SUPPORT FOR A TUBULAR ELECTRIC LAMP Filed March 17, 1966 3 Sheets-Sheet 1 b 11 i ii as 11 n AM MR W 21. 29 27 31' 3 INVENTORS: He rmunn Duhlhuus, Horst Giinter Nuchtrodt, Fritz Kniippel.

Y WMW Feb. 21, 1967 H. DAHLHAUS LIGHTING FIXTURE SUPPORT FOR A TUBULAR ELECTRIC LAMP Filed March 1'7, 1966 5 Sheets-Sheet 2 FIGA INVENTORS: Hermann Duhlhuus, Horst Biinter Nuchtrodt,

Fritz Knijppel. m M flew 2L Feb. 21, 1967 HDAHLHAUS 3,305,823

LIGHTING FIXTURE SUPPORT FOR A TUBULAR ELECTRIC LAMP Filed March 17, 1966 3 Sheets-Sheet 5 Fl I INVENTORS: Hermann Buhlhuus, Horst Giinter Nuchtrodt, Fritz Kniippel.

y lhmtwzm U W Unitcd States Patent "ice 3,305,823 LIGHTING FIXTURE SUPPORT FOR A TUBULAR ELECTRIC LAMP Hermann Dahlhaus, Am Ramsberg 12a, Ludenscheid, Germany; Horst Giinter Nachtrodt, Am Brutcnberg 37, Ludenscheid-Bierbaum, Germany; and Fritz Kniippel, Hoher Strasse 24, Stuttinghausen, Germany Filed Mar. 17, 1966, Ser. No. 535,224 Claims priority, application Germany, Oct. 5, 1961,

21,412; June 1, 1962, V 22,594

17 Claims. (Cl. 33953) This application is a continuation-in-part of our copending application Ser. No. 228,203, filed on Oct. 3, 1962, now abandoned.

This invention relates to lighting fixtures, and particularly to a lighting fixture for a tubular electric lamp such as a conventional fluorescent tube.

The known fixtures with the improvement of which this invention is more particularly concerned are equipped with two lamp holders spaced on a common support in the direction of the lamp axis. Spring contacts in the holders engage corresponding contact pins on the ends of the fluorescent tubes.

An object of the invention is the provision of a lighting fixture of the afore-described basic type which can be assembled from the constituent parts in a simple and secure manner without the use of tools, and can be wired without the use of tools, more specifically without the use of a screwdriver.

Another object is the provision of a lighting fixture which can be mass-produced at low cost, yet provides reliable and durable electric connections between an inserted lamp and a source of current.

A further object is the provision of a fixture which can be adjusted to receive fluorescent tubes which differ somewhat in their length.

An additional object is the provision of a fixture which consists of only a few parts, simple and inexpensive in themselves, not requiring critically close tolerances, and capable of being assembled by unskilled labor into the fixtures of the invention.

Yet another object is the provision of a fixture whose conductive parts consist of only two elements in each lamp holder, each of the elements being assembled with the remainder of the lamp holder in a simple manner without tools.

Other features, additional objects, and the attendant advantages of this invention will be readily appreciated by reference to the following detailed description of preferred embodiments when considered in connection with the accompanying drawings in which:

FIG. 1 shows a lighting fixture of the invention in front-elevational section;

FIG. 2 shows the fixture of FIG. 1 in fragmentary section on the line II-II of FIG. 1;

FIG. 3 illustrates the same fixture in fragmentary section on the line IIIIII of FIG. 1;

FIG. 4 illustrates a modification of the fixture of FIGS. 1 to 3 in front elevation, and partly in section analogous to FIG. 1; and

FIG. 5 shows the fixture of FIG. 4 in fragmentary plan view.

Referring now to the drawing in detail, and initially to FIGS. 1 to 3, there is seen a portion of a fixture for a single tubular fluorescent lamp consisting essentially of a support 1 having the shape of an elongated, shallow, inverted trough of sheet metal and of two lamp holders extending through openings 3 in the bottom of respective longitudinal end portions of the trough 1, only one of the lamp holders supported by the trough 1 being shown, the other one being identical in structure.

The lamp holder consists of five interlocking elements 3,305,823 Patented Feb. 21, 1967 which are a hollow shell 4, a rotor 5, two identical contact assemblies 6 in the shell 4 which hold the rotor in its position within the shell, and a retaining plate 7 which secures the contact assemblies in their respective positions.

The shell 4 is a unitary molding of a plastic material capable of resilient flexing when relatively thin. The portion of the shell 4 received in the trough 1 forms a base plate 8, thick enough to be quite rigid, approximately parallel to the surface of the support 1, and formed with an elongated rectangular opening 11 near one end thereof. The other end of the plate 8 carries an integral pin 12 which engages one of two apertures or recesses 13 in the support 1, and has two bores 10.

The portion of the shell 4 which extends upward through the opening 3 in the illustrated position of the fixture has a cross section conforming to the opening 11 and constitutes a receptacle 14. The front wall 15 of the receptacle has an approximately circular lamp-receiving opening 16 at the end thereof remote from the support 1, and a notch 17 leading radially into the opening 16. The base plate 8 projects forward beyond the front wall 15.

The rear wall 18, FIG. 3, rises flush from the rear edge of the base plate 8 and is imperforate. It has the same overall shape as the front wall, that of a rectangle having two corners rounded off in a semi-circle 19, FIG. 1.

The two narrow side walls 20, 21 are each formed with a slot 22, FIG. 3, having the shape of an upwardly open U. The walls 20, 21 are set back from the edge of the base plate 8 in such a manner as to define shoulders 23 on the base plate. The tong-shaped portions 24, 25 of the walls 20, 21 partly enveloped by the slots 22, increase in thickness toward the corresponding shoulders 23 so as to roject outward from the remainder of the wall, and have cam faces 26 on their projecting portions. As best seen in FIG. 1, each face 26 and the associated shoulder 23 define a recess which tapers inward of the cavity of the shell 4 and receives an edge portion of the support 1 at the opening 3. Each tong 24, 25 is capable of resilient pivotal movement about its thinnest portion which is contiguously adjacent the imperforate portion of the side wall. The afore-mentioned notch 17 separates the side walls at the top.

. A heavy integral rib 27 on the front wall 17 divides the portion of the shell cavity immediately below the opening 16 into two compartments receiving respective major portions of the two contact assemblies 6. Each assembly consists of three leaf springs 28, 29, 30. The largest spring 28 is bent into a downwardly closed U-shaped whose legs resiliently abut against the associated side wall 20 or 21 and the rib 27 which compress the spring. The bight portion of the spring 28 has openings 31, 31' the purpose of which will presently become apparent. An integral portion 32 of the spring leg near the :rib 27 arcuatcly engages an annular circumferential groove in the rotor 5.

Two integral lugs 33 on the same leg of the spring 28 and a rivet 34 attach the springs 29, 30 to the spring 28. The spring 29 is approximately V-shaped. One leg of the V-shape, which extends within the U-shape of the spring 28, is attached to the spring 28, whereas the other leg is longitudinally slotted, and its corrugated end is closely adjacent that leg of the spring 28 which abuttingly engages a side wall 20 or 21. The third spring 30, of relatively rigid material, provides an abutment which limits the deflection of the spring 29 in an upward direction or toward the rib 27 from the illustrated position.

The retaining plate 7 is a thin sheet of moderately resilient plastic having the approximate shape of an isosceles trapezoid. The edge of the plate 7 corresponding to the shorter parallel side of the trapezoid is held in abutting engagement with the bight portions of the two springs 28 by two integral fastening lugs 9 on the retaining plate 7 which are respectively received in the slots 22 and abut against the shoulders 23, thereby retaining the contact assemblies 6 in the cavity of the shell 4. Narrow ribs 35 on the front wall 15 and rear wall 18 assist in maintaining a precise predetermined position of the contact assemblies in the receptacle 14.

The rotor is held in coaxial alignment with the opening 16 of the front wall by the arcuate portions 32 of the springs 28. The circular front face of the rotor 5 is approximately flush with the outer surface of the front wall 15 and is formed with a groove 36 extending along a diameter and communicating with the afore-mentioned circumferential groove of the rotor.

The afore-described fixture is assembled without any tools in the following manner:

A rotor 5 is inserted into a shell 4 through the opening 11 in the base plate 8 while its groove 36 is aligned with the rib 27, the rib thus being temporarily received in the groove While the rotor is moved into its position near the opening 16. Two identical contact assemblies are then inserted into the compartments on either side of the rib 27 in such a manner that the concave face of the arcuate portions 32 on the spring are opposite each other, and ultimately engage the circumferential groove of the rotor 5. The retaining plate 7 is flexed sutficiently to permit its insertion through the opening 11, and is moved upwardly in the cavity of the shell 4 until it can expand into its normal relaxed shape by engagement of the lugs 9 with the slots 22. Assembly of one lamp holder is thereby completed, and a second lamp holder is assembled in the same manner.

A lamp holder is pushed through each opening 3 in the support 1 from the concave side of the trough in such a position that the axis of the circular opening 16 is parallel to the direction of elongation of the support. The width of the opening 3 is sufficient to pass most of the receptacle 14 freely, but it is smaller than the corresponding dimension of the base plate 8 and of the receptacle when measured across the projecting portions of the tongs 24, 25. The tongs are therefore deflected inward of the shell cavity while they pass through the opening 3, and the shoulders 23 ultimately abut against the bottom of the trough 1 while the tongs 24, 25 resiliently engage the outer face of the support 1, an edge portion of the support 1 being received in the tapering gap between each shoulder 23 and the associated tong.

The longitudinal or axial position of each lamp holder on the support 1 may be selected by engagement of the 2 pin 12 with one of the two associated longitudinally spaced apertures or recesses 13. If the use of lamps of only one fixed length in the fixture is contemplated, the lamp holder 2 may further be fastened to the support 1 by means of sheet metal screws inserted through the bores 10 in the base plate 8.

Under some conditions of use, the resilient pressure of the tongs 24, 25 against the edges of support 1 clamped between the tongs and the shoulders 23 is sufficient to prevent longitudinal displacement of the lamp holders 2 in the longitudinally oversized opening 3, and the outermost portion of the base plate 8 carrying the pin 12 may be snapped off if so desired.

The fixture has been described hereinabove in a position in which the receptacles 14 extend upward from the support 1 so that the notches 17 are upwardly open. It will be appreciated, however, that reference to specific directions is being made for the convenience of description only, and that the device is operative in any position in space, gravity not being relied upon for holding the elements of the fixture assembled with each other or with an inserted lamp. When the terminal pins of a lamp are to be inserted into the lamp holders in a conventional manner, the groove 36 of each rotor 5 is angularly aligned with the notch 17. The pins at the end of the lamp may then be slipped into a position symmetrical with respect to the axis of the rotor 5, and are engaged by the arcuate portions 32 of the spring 28 when the lamp is turned with the rotor 5 about this axis.

Current is supplied to the lamp by conductors which may be connected with each lamp holder without the use of tools. The bare end of an electric cable or Wire is introduced through the opening 11 in the base plate and through the opening 31 into the gap between the spring 29 and the associated leg of the spring 28. When the wire is fully introduced into the gap, it abuts against a hook shaped end portion of the spring 28. The increased resistance of the wire to further inward movement, and the fact that the wire cannot be pulled out of the lamp holder :by reasonable force indicates to the electrician that proper contact has been made. He does not have to see the free wire end nor the associated contact elements of the lamp holder.

When it is desired to disengage a connecting wire from the contact assembly, a screw driver or similar small, rodshaped object is introduced through the opening 31 of the spring 28 in such a manner as to deflect the spring 29 toward the relatively rigid abutment 30, thereby opening the gap between the free end of the spring 29 and the spring 28, and releasing a conductor clamped in the gap. The abutment 30 prevents a displacement of the spring 29 which could damage the contact assembly 6, and the increased resistance of the spring 29 to further displacement by the inserted object provides notice to the electrician that he may withdraw the connected wire.

The modified embodiment of the invention shown in FIGS. 4 and 5 differs from that illustrated in FIGS. 1 to 3 only by the means provided for securing the shell 4' on the trough-shaped support 1 against movement in the direction of the lamp axis.

The support 1' lacks the apertures or recesses 13, but its opening 3 through which the shell 4' of the lamp holder is passed during assembly is provided with two semicircular notches 38 in the edges thereof which are parallel to the lamp axis. The resilient tongs 24', 25' of the shell 4 are provided with approximately hemispherical projections 37 on their cam faces which are matingly received in corresponding notches 38 in the illustrated assembled condition of the fixture, and thereby prevent axial movement of the shell 4' in the opening 3. The lamp holder may be secured in a different axial position by shifting its projections 37 to other notches 38.

The base plate 8 projects forward beyond the remainder of the shell 4'. When axial pressure of an inserted lamp tends to pivot the shell 1' on the tongs 24', 25 the base plate 8' abuttingly engages the support 1 to limit the tilting movement. The base plate 8, as shown in FIG. 3, similarly limits counterclockwise tilting movement of the shell 4.

Many modifications and variations of the illustrated embodiments of the invention will readily suggest themselves to those skilled in the art. The oversized openings 3, 3' may be enlarged in an axial direction until they extend to the very ends of the supports 1, 1, and such an enlarged opening is preferably provided with the notches 38 for a wide choice of axial lamp holder positions.

The embodiments of the lighting fixture of the invention hereinbefore described with reference to the drawing are distinguished by simple structure which makes them inexpensive to manufacture. They may be assembled and wired without tools, or with the use of very simple tools readily handled by an unskilled operator. Yet they are reliable in their operation.

The simplicity of the fixture avoids critical dimensional relationships between the several assembled elements. The connection between current supplying conductors and the contact assemblies of the lamp holder is made without tools, and the mechanical and electrical characteristics of the connection are not unfavorably affected by manufacturing tolerances much greater than are cus tomary in this art. The non-conducting molded shell and the metallic conducting elements of the contact assemblies need not be closely matched to ensure perfect operation.

It should be understood, of course, that the foregoing disclosure relates only to preferred embodiments of the invention, and that it is intended to cover all changes and modifications of the examples of the invention herein chosen for the purposeof the disclosure which do not constitute departures from the spirit and scope of the invention set forth in the appended claims:

What we claim is:

1. A lamp holder for use in a lighting fixture for a tubular electric lamp comprising, in combination:

(a) a unitary shell having a base portion and a receptacle portion,

(1) the base portion having a face,

(2) the receptacle portion having a front wall, a rear wall, and two side walls connecting the front and rear walls, said walls extending from said base portion in a direction transverse to said face and defining a cavity in said receptacle portion, said base portion being formed with an opening therein communicating with said cavity,

(3) said side walls defining respective shoulders on said face and being each formed with a substantially U-shaped slot therethrough, the U- shape being open in said transverse direction away from said face, and the slot defining a tong portion of the side wall,

(4) said tong portion being resiliently pivotable relative to the remainder of the side wall inward and outward of the cavity, and normally projecting from said remainder in an outward lateral direction, and having a cam face opposite an associated shoulder when in the normal position thereof, and

(5) said front wall being formed with a lamp receiving opening having an axis substantially parallel to said face;

(b) two contact assemblies arranged in said cavity for simultaneous engagement with respective portions of a lamp received in said opening of the front wall; and

(c) securing means securing said assemblies to said receptacle portion.

2. A lamp holder as set forth in claim 1, wherein each shoulder and the associated cam face define a recess in said shell, the recess tapering in a direction inward of said cavity in said normal position of the corresponding tong portion.

3. A lamp holder as set forth in claim 2, wherein each tong portion decreases in lateral thickness in said transverse direction away from said cam face.

4. A lamp holder as set forth in claim 1, wherein said contact assemblies are each compressible in a plane parallel to said face, and received in said cavity for sliding movement in said transverse direction, and said securing means include abutment means integral with said shell and engaging each assembly for holding the same under compressive stress in said plane, a retaining member extending in said cavity between said base portion and the opening in said front wall and abuttingly engaging at least one of said assemblies in said transverse direction, and fastening means preventing movement of said retaining member outward of said cavity through said opening in said base portion.

5. A lamp holder as set forth in claim 4, wherein said fastening means include integral lug means on said retaining member engaging the slot in at least one of said side walls.

6. A lamp holder as set forth in claim 4, wherein each of said contact assemblies includes a plurality of spring members, a first one of said spring members having an approximately U-shaped part, and a second spring member having an approximately V-shaped part, each of said parts having two leg portions and a bight portion, the part of said second member being received in the U-shape of the first member, respective first leg portions of the members being fastened to each other, and the respective second leg portions defining a gap open toward the bight portion of said first spring member and toward said opening in the base portion, the bight portion of the first member being formed with an opening therethrough for passage of a conductor through said base portion and said bight portion into the gap between said second leg portions.

7. A lamp holder as set forth in claim 1, wherein each of said contact assemblies includes a plurality of spring members, a first one of said spring members having an approximately U-shaped part, and a second spring member having an approximately V-shaped part, each of said parts having two leg portions and a bight portion, the part of said second member being received in the U- shape of the first member, respective first leg portions of the members being fastened to each other, and the respective second leg portions defining a gap open toward the bight portion of said spring member and toward said opening in the base portion, the bight portion of the first member being formed with an opening therethrough for passage of a conductor through said base portion and said bight portion into the gap between said second leg portions.

8. A lamp holder as set forth in claim 1, wherein said face of the base portion projects beyond said front wall, and the shell further includes a pin portion extending from the projecting part of said face in said transverse direction.

9. A lamp holder as set forth in claim 1, wherein said shell further includes a projection on each of said cam faces.

10. A lighting fixture for a tubular electric lamp comprising, in combination:

(a) a support member, at least a portion of said support member consisting of sheetmaterial having two substantially parallel surfaces and being formed with an opening therethrough between said surfaces,

(b) a unitary lamp holder shell having a base portion and a receptacle portion,

(1) the base portion having a face adjacent one of said surfaces and approximately parallel thereto,

(2) the receptacle portion having a front wall, rear wall, and two side walls connecting the front and rear walls, said walls extending from said said base portion in a direction transverse to said face through said opening in the support member and defining a cavity in the receptacle portion, said base portion being formed with an opening therein communicating with said cavity,

(3) said side walls defining respective shoulders on said face and being each formed with a substantially U-shaped slot therethrough, the U-shape being open in said transverse direction away from said face and the slot defining a tong portion of said side wall,

(4) said tong portion being resiliently pivotable relative to the remainder of said side wall in ward and outward of said cavity, and normally projecting from said remainder in an outward lateral direction, the tong portion having a cam face opposite an associated shoulder when in the normal position thereof,

(5) each shoulder and the associated cam face defining a recess in said shell, said recess tapering in a direction laterally inward of said cavity in said normal position of the corresponding tong portion,

7 (6) said front wall being formed with a lampreceiving opening having an axis substantially parallel to said surfaces of said support member, (7) said portion of the support member having two axially elongated edge-parts contiguously adjacent said opening of the support member and respectively received in said recesses in abutting engagement with the shoulder and cam face defining the recess,

((1) two contact assemblies arranged in said cavity for simultaneous engagement with respective portions of a lamp received in said opening of said front wall, and

(d) securing means securing said assemblies to said receptacle portion.

11. A fixture as set forth in claim 10, wherein said support member is elongated in the direction of said axis, and said opening in the support member is dimensioned to permit axial movement therein of the lamp holder shell.

12. A fixture as set forth in claim 11, wherein said face of the base portion projects axially beyond said front wall, and the shell further includes a pin portion extending from the projecting portion of said face in said transverse direction, the support member being formed with a plurality of axially spaced recesses engageable by said pin portion in respective axial positions of the shell in said opening of the support member.

13. A fixture as set forth in claim 1, wherein said support member is formed with a plurality of axially spaced notches in each of said edge parts, and the shell further includes a projection on each of said cam faces engageable with respective notches in a plurality of axially spaced positions of the shell in said opening of the support member.

14. A fixture as set forth in claim 10, wherein each of said contact assemblies includes a plurality of spring members, a first one of said spring members having an approximately U-shaped part, and a second spring member having an approximately V-shaped part, each of said parts having two leg portions and a bight portion, the part of said second member being received in the U-shape of the first member, respective first leg portions of the members being fastened to each other, and the respective second leg portions defining a gap open toward the bight 8 portion of said first spring member and toward said opening in the base portion, the bight portion of the first member being formed with an opening therethrough for passage of a conductor through said base portion and said bight portion into the gap between said second leg portions.

15. A fixture as set forth in claim 14, wherein the bight portion of said first spring member is formed with yet another opening therethrough approximately aligned with the bight portion of said second spring member for insertion of a tool, whereby the second leg portion of said second spring member may be deflected away from the second leg portion of the first spring member for thereby widening said gap and releasing a conductor held therein, the contact assembly further comprising abutment means fastened to said first leg portions and positioned to limit deflection of said second spring member by said tool.

16. A fixture as set forth in claim 14, wherein one spring member of each contact assembly has an arcuate contact portion extending about said axis, the fixture further comprising a rotor member in said cavity having an annular groove about said axis, said arcuate contact portions being at least partly received in said groove and rotatably holding said rotor member in coaxial alignment with the lamp receiving opening of said front wall.

17. A fixture as set forth in claim 16, wherein said securing means include a resilient retaining member in said cavity abuttingly engaging said contact assemblies in said transverse direction, respective portions of said retaining members laterally extending into said slots of the side walls for securing the retaining member against movement in said transverse direction outward of said cavity.

References Cited by the Examiner UNITED STATES PATENTS 2,729,799 1/1956 Pistey 339--52 2,765,397 10/1956 Harris 339 X 3,064,225 11/1962 Lennox 33957 X 3,079,581 2/1963 Klumpp 339l28 3,116,098 12/1963 Kulka 33956 3,246,320 5/1966 Honbolt 339l28 X EDWARD C. ALLEN, Primary Examiner.

ALFRED S. TRASK, Examiner. 

1. A LAMP HOLDER FOR USE IN A LIGHTING FIXTURE FOR A TUBULAR ELECTRIC LAMP COMPRISING, IN COMBINATION: (A) A UNITARY SHELL HAVING A BASE PORTION AND A RECEPTACLE PORTION, (1) THE BASE PORTION HAVING A FACE, (2) THE RECEPTACLE PORTION HAVING A FRONT WALL, A REAR WALL, AND TWO SIDE WALLS CONNECTING THE FRONT AND REAR WALLS, SAID WALLS EXTENDING FROM SAID BASE PORTION IN A DIRECTION TRANSVERSE TO SAID FACE AND DEFINING A CAVITY IN SAID RECEPTACLE PORTION, SAID BASE PORTION BEING FORMED WITH AN OPENING THEREIN COMMUNICATING WITH SAID CAVITY, (3) SAID SIDE WALLS DEFINING RESPECTIVE SHOULDERS ON SAID FACE AND BEING EACH FORMED WITH A SUBSTANTIALLY U-SHAPED SLOT THERETHROUGH, THE USHAPE BEING OPEN IN SAID TRANSVERSE DIRECTION AWAY FROM SAID FACE, AND THE SLOT DEFINING A TONG PORTION OF THE SIDE WALL, (4) SAID TONG PORTION BEING RESILIENTLY PIVOTABLE RELATIVE TO THE REMAINDER OF THE SIDE WALL INWARD AND OUTWARD OF THE CAVITY, AND NORMALLY PROJECTING FROM SAID REMAINDER IN AN OUTWARD LATERAL DIRECTION, AND HAVING A CAM FACE OPPOSITE AN ASSOCIATED SHOULDER WHEN IN THE NORMAL POSITION THEREOF, AND (5) SAID FRONT WALL BEING FORMED WITH A LAMP RECEIVING OPENING HAVING AN AXIS SUBSTANTIALLY PARALLEL TO SAID FACE; (B) TWO CONTACT ASSEMBLIES ARRANGED IN SAID CAVITY FOR SIMULTANEOUS ENGAGEMENT WITH RESPECTIVE PORTIONS OF A LAMP RECEIVED IN SAID OPENING OF THE FRONT WALL; AND (C) SECURING MEANS SECURING SAID ASSEMBLIES TO SAID RECEPTACLE PORTION. 